Electric switch



C. D. PLATT- ELECTRIC SWITCH. APPLICATION FILED MAY 1, 1919.

Patented Apr. 20, 1920.

INVENTOR 'lamizcefli AT); RNEY UNITED STATES PATENT OFFICE.

CLARENCE D. PLATT, OF BRIDGEPORT, CONNECTICUT.

ELECTRIC SWITCH.

Application filed May 1, 1919.

To all "whom it may concern Be it known that I, CLARENCE D. PLATT, a citizen of the United States of America, residing at Bridgeport, Connecticut, have invented a new and useful Electric Switch, of which the following is a specification.

My present invention relates particularly to the contact mechanism of electric switches, the objects of the invention being primarily to provide switch contacts of simple construction which will have a high current carrying capacity.

Other objects of the invention are to insure good electrical contact and to eliminate arcing or burning of the contact faces.

Briefly stated, the invention consists of a special substantially C-shaped contact mounted for movement toward and away from the relatively stationary contacts, said contact being constructed of a strip of spring metal and adapted to have the inturned freely yielding ends thereof forced into fiat engagement with the stationary contacts. The ends of this C-shaped contact are preferably formed with outwardly directed lugs, which in the circuit breaking operation constitute terminals to take care of any are which may form or tend to form.

For the sake of a more complete disclosure of the invention attention is invited to the accompanying drawing wherein .I have shown the invention embodied in a practical and commercial form. It will be understood however, that the structure may be modified in certain respects without departure from the true spirit and scope of the invention.

Figure 1 of said drawing is a plan View of an inclosed switch, the cover being open and shown as broken away.

Fig. 2, is a broken sectional view taken substantially on the plane of the line 2-2 of Fig. 1. In this view the parts are indicated as in the circuit-closing movement.

Fig. 8, is a sectional view similar to Fig.

2 showing the switch parts in the entirely closed position.

Fig. 4, is a view of the same parts showing the switch at the moment of break in the circuit-opening operation.

Fig. 5, is a detail perspective view of one of the movable spring contacts.

The switch illustrated is of the double pole type embodying two pairs of spaced contacts 7 and 8 shown simply as fiat strips Specification of Letters Patent.

Patented Apr. 20, 1920.

Serial No. 294,044.

support in the form of a movable cross bar 15 slidably guided on the pins 17 upstanding from the base. The contact springs are secured to the supporting bar by screws 16 and it will be noted with this construction that the back portions of the springs are engaged by the support only at the points where they are secured thereto and that the ends of the back portions extending to opposite sides of thesupporting bar are free of said support and can yield in both directions.

A spring 18 is shown engaging with the cross bar for shifting the movable switch element in circuit-opening direction and mechanism for shifting this element in the opposite direction is shown in the form of a lever 19 which engages with a bearing plate 20 on the top ofthe supporting. bar 15 and which lever is actuated by a lug 21 on the operating shaft 22, said lug engaging with spaced stops 23, 24on the lever 19. The shaft 22 is provided with a suitable handle 25 disposed at the outside of the box 26 in which the switch is mounted.

In closingthe switch, the handle 25 is rockeddownwardly as indicated in Fig. 2 to carry the lug 21 into engagement with the stop 24, whereupon the lever 19 operates as a cam against the bearing plate 20 to force the support toward the switch base. In this movement the tips of the C-shaped contact springs are first brought into engagement with the ends of the spaced flat contacts and as the movemert continues these bent-under ends flatten out as indicated in Fig. 3 into fiat engagement with the stationary contacts, forming contact pads of relatively wide area and consequently great current carrying capacity.

The parts are preferably so designed that.

' rupturing thecircuit with a quick break wardly as indicated in Fig. 4, the lug 21 in this case engaging the stop 23 and rocking the lever 19 out of holding engagement with the bearing plate. As the lever 19 swings downwardly, a point is reached where the spring 18 asserts itself and snaps the movable switch element quickly outward The parts are illustrated in Fig. t as approximately at the moment when the spring is acting to snap the movable switch element to the open-circuit position. To guard the movable contacts against injurious arcing at such time, I preferably provide the ends of the contact spring with angularly and outwardly extending lugs 27 which, in the closed position of the switch over-lie the ends of the stationary contacts as indicated in Fig. 3 and which, in the circuit opening movement, provide the nearest points to the ends of the stationary contacts and hence form terminals for the arcs, in case'there is a tendency for the production of an are or arcs. These lugs thus provide points which can be burned more or less without injuring the normal current-carry ing parts of the switch.

I claim:

1. In a double break electric switch, the combination of spaced contacts having exposed contact faces disposed in substantially the same plane, a bridging contact comprising a strip of spring metal having reversely bent free end portions and means for forcing said bent under end portions into fiat engiagement with the contact faces aforesa1 2. In an electric switch, the combination with spaced contacts, of a bridging contact comprising a strip of spring metal having a back portion and reversely bent free end portions disposed beneath said back portion and adapted for engagement with the spaced contacts and means for moving the bridging contact bodily and forcing both ends into engagement with the'spaced contacts, said means being constructed to buckle the back portion of said bridging contact to thereby increase the spring tension of said contact against the spaced contacts. Y

3. In a switch of the character described, the combination of spaced contacts, a substantially C-shaped bridging contact having inturned end portions for flat engagement with the spaced contacts and angularly bent tips at the ends of said inturned end portions and providing arcing terminals overlying the ends of the spaced contacts in the closed condition of the switch.

4. In a double break switch of the character described, spaced contacts, a bridging contact comprising a flexible strip having a normally outwardly bowed back portion and inturned free end portions doubled under said back portion-and operating means for forcing both of said bent under end portions of the contact strip into engagement with the spaced contacts, said operating means having a movement in the circuit closing direction sufiicient to buckle the normally outwardly bowed back of the contact in the opposite direction.

5. In a switch of the character described, the combination of spaced contacts and a bridging contact having reversely bent end portions engaging the faces of the spaced contacts and angularly bent tips extending over but spaced from the ends of the spaced contacts.

CLARENCE D. PLATT. 

